Since the war on drugs began, the incarceration rate for women in the US has increased by more than 800% Photograph: Guillermo Arias/AP

In 1971, president Richard Nixon declared a war on drugs that was supposed to end the scourge of addiction by drastically expanding the net of imprisonable drug offenses and imposing extremely harsh sentences on anyone involved in the drug trade, including small time dealers and users. Last year, the war on drugs, which has so far cost the taxpayer $1 trillion give or take, reached its 40th birthday – but with little cause to celebrate. The drug problem is more or less what it ever was, and the so-called war has wreaked havoc on the most vulnerable communities it was supposed to rescue, while dealing a particularly devastating blow to women and children.

Since the so called war began, the incarceration rate for women in the US has increased by more than 800%, almost double the rate of increase for the male prison population. In 1980, there were just over 13,000 women in state and federal prisons; by 2010 that number had jumped to over 112,000 women. When you combine that with the local jail population, it jumps to over 200,000. Over half of that extraordinary increase is attributable to drug offenses, including possession for personal use, stealing to feed a habit, or small time dealing often to supplement an impossibly low income. As with all things prison, the drug war has not been colour blind. White women use drugs at a slightly higher rate than black women, yet black women are three times more likely than white women to be incarcerated for drug offenses.

When in 2004, Martha Stewart was serving out her time at the Alderson correctional facility in Georgia for an insider trading charge, she was surrounded by many women caught up in the drug war net, and she rightly attempted to draw attention to their cause:

So many of the women here will never have the joy and well being that you and I experience. Many of them have been here for years – devoid of care, devoid of love, devoid of family. I beseech you to think about these women, to encourage the American people to ask for reforms, both in sentencing guidelines, in length of incarceration for non-violent first time offenders and for those involved in drug-taking. They would be much better served in a true rehabilitation center than in prison where there is no real help, no real programs to rehabilitate, no programs to educate, no way to be prepared for life 'out there' where each person will ultimately find herself, many with no skills and no preparation for living

What Stewart was trying to point out was what should be blindingly obvious: that drug addicts need treatment, not punishment, and they certainly not need prison, which serves only to exacerbate the causes of addiction rather than cure them. A 2004 report by the ACLU titled Caught in the Net profiles the kind of women most likely to end up behind bars for drug offenses. They tend to be low income, have limited educational and work opportunities, are frequently victims of violence, and, of course, the majority are women of colour. Whoever decided that adding a prison sentence to the mix would cure these women of their problems, clearly didn't think it through.

The advantages of drug treatment rather than prison is clearly illustrated in Alisha Ruiz' story. Both of Alisha's parents had substance abuse issues while she was growing up and so, somewhat inevitably, she began using drugs herself at the age of 13 and quickly became addicted to crystal meth. This addiction and the petty crimes she committed to feed it led to several stints in juvenile detention. Shortly after giving birth to her daughter at age 15, she was arrested for a vehicular manslaughter charge and three years later, at age 18, she was sent to prison for a year. When she got out, she had nowhere to go, no job prospects and no means of supporting herself. She was rearrested soon after for drug taking and was about to be sentenced to four more years in prison when she begged the judge to send her to a treatment program instead: "If he had sent me to prison, I would barely be getting out right now. I had been in and out of jails my whole life, prison wasn't going to do anything for me. If anything, it would have made things worse."

Alisha was extremely fortunate that the judge was opted to give her a second chance, but also that he was not bound by federal mandatory sentencing rules and able to exercise discretion (in 2000, California passed the Substance Abuse and Crime Prevention Act (SACPA) that requires drug treatment for non violent offenders convicted of drug possession for personal use).

Since completing the drug treatment program, Alisha has transformed her life. She got a job working in the Homegirl Café in Los Angeles. She has regained custody of her daughter, who is now doing well at school, and is about to start a training program with a master chef. She would be the first to acknowledge, however, that she would never have been able to overcome the disadvantages which led to her drug abuse without some state intervention. A four year stint in prison would have cost the taxpayer well over $100,000; her drug treatment cost nothing near that sum. It's so much better for her and for society as a whole that the state chose the humane and cost effective option.